1. Field of the Invention
The present invention relates generally to the distribution of power in a data storage system and, more particularly, to a segmented power strip for distributing power to an automated robotic device for use in a tape cartridge library system.
2. Background
Current automated libraries for tape cartridges typically include arrays of multiple storage cells housing the tape cartridges, as well as multiple media drives. Multiple automated robotic devices may be used to move tape cartridges between the various storage cells and media drives within a library.
As described in detail below, the use of multiple robotic devices in automated tape cartridge libraries raises various problems concerning the distribution of power to such robotic devices. More particularly, robotic devices used in automated tape cartridge libraries require power for operation thereof. In prior art automated tape cartridge libraries, the movement of the robotic devices is restricted by wire cable connections used for providing such power. That is, such cabling can prevent the robotic devices from crossing paths, or from continuous movement in one direction around the library without the necessity of ultimately reversing direction.
Such problems can be overcome through the use of brush/wiper technology. A robotic device traveling over a given route may use power distributors such as fixed conductive strips to supply power to the robotic device, which itself is provided with brushes or wipers that contact the conductive strips in order to conduct power to the robotic device. Multiple brushes are preferably used on each robotic device to improve robustness and reliability. The integration of such conductive strips into the automated tape cartridge library, in conjunction with brush contacts provided on the robotic devices, allows for greater freedom of movement of the robotic devices, as well as for modular and extensible power distribution to robotic devices as library configurations change, or as libraries are connected in a modular fashion to form library systems.
In that regard, such conductive strips may be provided in sections. That is, segmented power conductors or strips may be used to supply electrical power to such robotic devices. Such power strips are joined together along a path or guide rail on which a robotic device moves in the library. When used in such a fashion for power transmission, segmented power strips will be sensitive to alignment so as not to create a sloppy joint. A mis-aligned joint in the power strip may cause a brush to lose contact with a power strip due to bounce. Wear on the brushes and power strip pieces at the joints may also cause limited life of the joint.
As a result, there exists a need for an improved segmented power strip and a method for joining such power strips. Such an improvement would preferably include a pre-loaded and overconstrained joint which would cause the power strips in the robot guide rail to substantially align. Such an improvement would preferably include conductors slightly longer than the supporting structure of the robot guide rail, so as to force adjoining conductors into contact at their ends as guide rails and conductors are assembled. In addition, adjoining ends of conductors would preferably be beveled or angled such that a force urging the conductors together causes the conductors to slip laterally against each other, so as to again facilitating alignment at the joint. Such a bevel or angle would also spread out the wiping action of a brush as it traverses the joint, thereby prolonging the life of the joint and brush, and limiting any problems that may arise as a result of any small offset. Still further, the power strips would preferably be pre-loaded or biased by a spring load, thereby causing the joint to stay in compression for the life of the joint.
Accordingly, the present invention provides for improved power distribution to an automated robotic device in a data storage library using a segmented power strip.
According to the present invention, then, a segmented power strip is provided for supplying electrical power to an automated robotic device for use in a data storage system having a guide rail, wherein the automated robotic device is adapted to move along the guide rail. The segmented power strip comprises a first substantially planar member having an end, the first member comprising a conductor for making electrical contact with the automated robotic device, and a second substantially planar member having an end, the second member comprising a conductor for making electrical contact with the automated robotic device. The first and second members are assembled to create a joint where the conductor of the first member is proximate the conductor of the second member such that the automated robotic device maintains electrical contact with at least one conductor as the automated robotic device traverses the joint, and the ends of the first and second members are adapted to cooperate such that at least one of the first and second members moves laterally relative to the other of the first and second members during assembly thereof. The power strip further comprises means for biasing at least one of the first and second members against lateral motion relative to other of the first and second members.
Also according to the present invention, a method is provided for joining a segmented power strip for supplying electrical power to an automated robotic device for use in a data storage system having a guide rail, wherein the automated robotic device is adapted to move along the guide rail. The method comprises providing a first substantially planar member having an end, the first member comprising a conductor for making electrical contact with the automated robotic device, and providing a second substantially planar member having an end, the second member comprising a conductor for making electrical contact with the automated robotic device. The first and second members are assembled to create a joint where the conductor of the first member is proximate the conductor of the second member such that the automated robotic device maintains electrical contact with at least one conductor as the automated robotic device traverses the joint, and the ends of the first and second members are adapted to cooperate such that the at least one of the first and second members moves laterally relative to the other of the first and second members during assembly thereof. The method further comprises providing means for biasing at least one of the first and second members against lateral motion relative to other of the first and second members.
According to another embodiment of the present invention, a segmented power strip is provided for supplying electrical power to an automated robotic device for use in a data storage system having a guide rail, wherein the automated robotic device is adapted to move along the guide rail. The segmented power strip comprises a first substantially planar elongated member having first and second sides and an end, the first side having a first electrically conductive strip thereon for making electrical contact with the automated robotic device, the first conductive strip having an electrical charge, the second side having a second electrically conductive strip thereon for making contact with the automated robotic device, the second conductive strip having an electrical charge opposite the electrical charge of the first conductive strip. The power strip further comprises a second substantially planar elongated member having first and second sides and an end, the first side having a first electrically conductive strip thereon for making electrical contact with the automated robotic device, the first conductive strip having an electrical charge, the second side having a second electrically conductive strip thereon for making contact with the automated robotic device, the second conductive strip having an electrical charge opposite the electrical charge of the first conductive strip. The first and second members are assembled to create a joint where the first and second conductive strips of the first member are proximate the first and second conductive strips of the second member, respectively, such that the automated robotic device maintains electrical contact with at least one first conductive strip and at least one second conductive strip as the automated robotic device traverses the joint, and the ends of the first and second members are adapted to cooperate such that at least one of the first and second members moves laterally relative to the other of the first and second members during assembly thereof. The power strip still further comprises means for biasing at least one of the first and second members against lateral motion relative to the other of the first and second members.
Still further according to another embodiment of the present invention, a method is provided for joining a segmented power strip for supplying electrical power to an automated robotic device for use in a data storage system having a guide rail, wherein the automated robotic device is adapted to move along the guide rail. The method comprises providing a first substantially planar elongated member having first and second sides and an end, the first side having a first electrically conductive strip thereon for making electrical contact with the automated robotic device, the first conductive strip having an electrical charge, the second side having a second electrically conductive strip thereon for making contact with the automated robotic device, the second conductive strip having an electrical charge opposite the electrical charge of the first conductive strip. The method also comprises providing a second substantially planar elongated member having first and second sides and an end, the first side having a first electrically conductive strip thereon for making electrical contact with the automated robotic device, the first conductive strip having an electrical charge, the second side having a second electrically conductive strip thereon for making contact with the automated robotic device, the second conductive strip having an electrical charge opposite the electrical charge of the first conductive strip. The first and second members are assembled to create a joint where the first and second conductive strips of the first member are proximate the first and second conductive strips of the second member, respectively, such that the automated robotic device maintains electrical contact with at least one first conductive strip and at least one second conductive strip as the automated robotic device traverses the joint, and the ends of the first and second members are adapted to cooperate such that at least one of the first and second members moves laterally relative to the other of the first and second members during assembly thereof. The method further comprises providing means for biasing at least one of the first and second members against lateral motion relative to the other of the first and second members.
The above features, and other features and advantages of the present invention are readily apparent from the following detailed descriptions thereof when taken in connection with the accompanying drawings.